heat treat oven blues..

swede2207

swede2207

Joined
Mar 10, 2002
Messages
323
Hey fellas i have a bit ofa delimma. I have recentlyacquired a heat treat oven and an analog controller to go with it..thats not the delimma..the oven itself was made by swest ,and the controller is a paragon km14. The delimma is the oven has 2 sets of coils and was wired for 240..and the controller is wired for 110 and will run only one set of coils..
Here is my plan..to hook the controller up to only one set of coils and see if it will get to temperature(i dont care if it takes longer )..Problem is it only had one pyrometer? (the ceramic coated wires that detect temp) and it is hooked up to the thermocoupler which kicks the unit on and off ..i need another one for the thermometer side that tells me what temp it is inside the oven.
If your still with me ..i might entertain buying a 240 volt controller if such an animal exists..but i dont know where to get any of this stuff..my calls to paragon have yet to be answered ..guess theyre on a different schedule than i am..anyway any thoughts suggestions etc..would be greatly appreciated.
Luke
 
All you have to do is hook the 110 controller to a relay with contacts rated at 220.It should have a 110V coil. Have an electrical friend help you if you are not familiar with hooking up relays.
Stacy
 
rashid11, please forgive my electronic ignorance..is there a simple way to explain how i could "digitize" my oven .. i dont really understand the pid and ssr etc..could you explain it in terms an idiot could understand? thanks..Luke
 
Sure thing:

- the SSR is a relay, a valve, if you will. When a signal is applied to it's control input, the "valve" opens, so that the current can flow. SSR has 4 contacts - you apply control voltage to 2 contacts, 1 is "current in" and 1 is "current out".

SSR is really the best way to go to control the current. The "regular" electro-mechanical relays wear out rather quickly, as contacts arc when turning current on and off (it is no ez task to interrupt 20A of flow @ 220V). SSRs don't have this problem and last forever

- the thermocouple produces voltage that depends on ambient temp. Different types exist, tailored toward different temp ranges, but the one you need is called "K-type". It needs to be properly protected to survive 2000F. Inconel is commonly used for protection

- now you attach the tc output (2 wires) to a PID controller. You connect the SSR control output of PID contoller to the SSR relay control pins (2 wires). You attach one leg of power circuit to one of the output contacts of SSR , second output contact of SSR is attached to one end of heating coil,
and the other end of coil is attached to the other leg of power circuit.

PID contollers also require some form of power - the better ones take ANYTHING: 12-280DC or 12-280AC.

Here's how it all works, simplified:


1 the wire heats up the interior


2 when SSR relay lets current flow through the wire


3 when controller tells it to let the current flow


4 when controller senses, from the thermocouple temperature probe, that
temperature needs to go up


5 to reach whatever temperature you set up on the said controller



Here is more on the subject:

http://groups.google.com/group/rec....ver+temperature+oven+&rnum=1#502c311454a799ec

Disclaimer: you need to know whatcha doing, do it at your own risk, seek a help of licensed electrician blah blah blah
 
Thanks for the help guys..upon further inspection..i noticed the two heating element coils were hooked together with a small wire..i hooked up one set of coils to the controller and hit the switch..and sure enough it started to get hot..now the thermocouple that im missing is the one that reads the temperature inside the oven..so i dont know how hot it got on one set of coils..is it possible that i could hook up the other set of coils with the small wire as it was before..im concerned about what amperage it would draw..the controller says 5 amps..but this is where i get a little confused..
 
I'd have someone who knows appliances take a look for you.It sounds like the controller is rated at 5 amps.That won't run a HT oven.For a HT oven,the 220V draw should be around 10-15 amps,110V would draw 20-30 amps.There is not enough information to know what kind of oven you got,what the coils will draw,and what the controller is rated for.Again, get someone who knows to take a look before you send it up in smoke.Statements like "Hooked up with a small wire" ,don't go with "Heating Elements". Working with 110V and 220V are not like making your first knife
- the mistakes can be permanent.
 
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